Described herein are structures, systems, and methods for placement of an ocular device on an eye that may be used to treat the eye. Provided are various implementations of ocular devices used for drug delivery, along with methods for using ocular devices positioned on or near the anterior surface of the eye. The devices may be worn along an anterior surface of the eye outside the optical zone, and can deliver therapeutically efficacious amounts of one or more therapeutic agents.
A variety of ophthalmic and non-ophthalmic conditions necessitate administration of various drugs to the eye. Eye drops and gels can be effective drug delivery vehicles, but can also have significant disadvantages. Specifically, eye drops mix with fluid in the tear film, but may have a residence time of only 2-5 minutes in the tear film. As little as 5% of the drug may be absorbed locally; some or all of the rest being carried from the lacrimal sac into the lacrimal duct, which can have potentially undesirable effects. Consequently, most of the drug may be wasted with less than ideal amounts delivered to the targeted tissue. Also, the presence of the drug in the bloodstream may have potentially harmful side effects. Gels may adhere more effectively to the eye, but can also blur the patient's vision. Both eye drops and gels may need to be reapplied frequently for some therapies, and patients may not administer the eye drops or gels as frequently as directed in at least some instances, such that the amount of drug delivered can be less than ideal. For example, in at least some instances a substantial number of patients may not refill their prescription after one year, and the substantial number of patients can be up to fifty percent in some instances. Alternatives to eye drops and gels include treatments in which insert structures containing or impregnated with drugs have been placed under an eyelid, in a punctum, or on the cornea with drug-impregnated contact lenses, and the like.